Some bits of randao

beacon_chain.nimble

@@ -4,7 +4,7 @@ author        = "Status Research & Development GmbH"
 description   = "Eth2.0 research implementation of the beacon chain"
 license       = "MIT or Apache License 2.0"
 installDirs   = @["beacon_chain"]
-bin           = @["beacon_chain/beacon_node"]
+bin           = @["beacon_chain/beacon_node", "beacon_chain/validator_keygen"]
 
 ### Dependencies
 requires "nim >= 0.18.0",

beacon_chain/beacon_node.nim

@@ -80,6 +80,7 @@ proc addLocalValidators*(node: BeaconNode) =
     # 1. Parse the validator keys
     let privKey = loadPrivKey(validator)
     let pubKey = privKey.pubKey()
+    let randao = loadRandao(validator)
 
     # 2. Check whether the validators exist in the beacon state.
     #    (Report a warning otherwise)
@@ -89,7 +90,7 @@ proc addLocalValidators*(node: BeaconNode) =
     else:
       # 3. Add the validators to node.attachedValidators
       # TODO: Parse randao secret
-      node.attachedValidators.addLocalValidator(idx, pubKey, privKey, @[])
+      node.attachedValidators.addLocalValidator(idx, pubKey, privKey, randao)
 
 
 proc getAttachedValidator(node: BeaconNode, idx: int): AttachedValidator =
@@ -114,6 +115,8 @@ proc proposeBlock(node: BeaconNode,
   # TODO:
   # 1. Produce a RANDAO reveal from attachedVadalidator.randaoSecret
   # and its matching ValidatorRecord.
+  let randaoCommitment = node.beaconState.validator_registry[validator.idx].randao_commitment
+  proposal.randao_reveal = await validator.randaoReveal(randaoCommitment)
 
   # 2. Get ancestors from the beacon_db
 

beacon_chain/conf.nim

@@ -1,5 +1,5 @@
 import
-  confutils/defs, spec/crypto, milagro_crypto
+  confutils/defs, spec/crypto, milagro_crypto, randao
 
 type
   ValidatorKeyPath* = distinct string
@@ -28,11 +28,11 @@ type
 proc loadPrivKey*(p: ValidatorKeyPath): ValidatorPrivKey =
   initSigKey(cast[seq[byte]](readFile(string(p) & ".privkey")))
 
+proc loadRandao*(p: ValidatorKeyPath): Randao =
+  initRandao(cast[seq[byte]](readFile(string(p) & ".randao")))
+
 proc parse*(T: type ValidatorKeyPath, input: TaintedString): T =
-  discard loadPrivKey(ValidatorKeyPath(input))
-
-  # TODO:
-  # Check that the entered string is a valid base file name and
-  # that it has matching .privkey, and .randaosecret files
-  T(input)
+  result = T(input)
+  discard loadPrivKey(result)
+  discard loadRandao(result)
 

beacon_chain/randao.nim

@@ -0,0 +1,64 @@
+import spec/digest
+
+type Randao* = object
+  seed: Eth2Digest
+
+const MaxRandaoLevels = 10000
+
+proc initRandao*(seed: Eth2Digest): Randao =
+  result.seed = seed
+
+proc initRandao*(bytes: openarray[byte]): Randao =
+  if bytes.len != sizeof(Eth2Digest):
+    raise newException(Exception, "Wrong randao size")
+  var s: Eth2Digest
+  s.data[0 .. ^1] = bytes
+  initRandao(bytes)
+
+func repeatHash*(h: Eth2Digest, n: int): Eth2Digest =
+  if n == 0: h
+  else: repeatHash(eth2Hash(h.data), n - 1)
+
+iterator items(r: Randao): Eth2Digest =
+  var h = r.seed
+  for i in 0 .. MaxRandaoLevels:
+    yield h
+    h = eth2hash(h.data)
+
+proc initialCommitment*(r: Randao): Eth2Digest =
+  var i = 0
+  for h in r:
+    if i == MaxRandaoLevels:
+      return h
+    inc i
+
+  assert(false, "Unreachable")
+  
+proc reveal*(r: Randao, commitment: Eth2Digest): Eth2Digest =
+  if commitment == r.seed:
+    raise newException(Exception, "Randao: cannot reveal for seed")
+  result = r.seed
+  for h in r:
+    if h == commitment:
+      return
+    result = h
+
+  raise newException(Exception, "Randao: commitment not found")
+
+when isMainModule:
+  import times, nimcrypto
+  var seed: Eth2Digest
+  let r = initRandao(seed)
+
+  var s = epochTime()
+  var ic = r.initialCommitment()
+  var e = epochTime()
+  echo "initialCommitment: ", ic
+  echo "Took time: ", e - s
+  s = epochTime()
+  let rev = r.reveal(ic)
+  e = epochTime()
+  echo "reveal: ", rev
+  echo "Took time: ", e - s
+
+  echo r.reveal(eth2hash([1.byte, 2, 3]))

beacon_chain/validator_keygen.nim

@@ -0,0 +1,37 @@
+import os, ospaths, milagro_crypto, nimcrypto, ./spec/digest
+
+proc writeFile(filename: string, content: openarray[byte]) =
+  var s = newString(content.len)
+  if content.len != 0:
+    copyMem(addr s[0], unsafeAddr content[0], content.len)
+  writeFile(filename, s)
+
+proc genKeys(path: string) =
+  let pk = newSigKey()
+  var randaoSeed: Eth2Digest
+  if randomBytes(randaoSeed.data) != sizeof(randaoSeed.data):
+    raise newException(Exception, "Could not generate randao seed")
+
+  createDir(parentDir(path))
+  let pkPath = path & ".privkey"
+  let randaoPath = path & ".randao"
+  writeFile(randaoPath, randaoSeed.data)
+  writeFile(pkPath, pk.getRaw())
+  echo "Generated privkey: ", pkPath
+  echo "Generated randao seed: ", randaoPath
+
+proc printUsage() =
+  echo "Usage: validator_keygen <path>"
+
+proc main() =
+  if paramCount() != 1:
+    printUsage()
+    return
+
+  let path = paramStr(1)
+  genKeys(path)
+
+
+when isMainModule:
+  main()
+

beacon_chain/validator_pool.nim

@@ -1,7 +1,7 @@
 import
   tables, random,
   asyncdispatch2,
-  spec/[datatypes, crypto]
+  spec/[datatypes, crypto, digest], randao
 
 type
   ValidatorKind = enum
@@ -10,14 +10,12 @@ type
 
   ValidatorConnection = object
 
-  RandaoSecret = seq[byte]
-
   AttachedValidator* = ref object
-    idx*: int
+    idx*: int # index in the registry
     case kind: ValidatorKind
     of inProcess:
       privKey: ValidatorPrivKey
-      randaoSecret: RandaoSecret
+      randaoSecret: Randao
     else:
       connection: ValidatorConnection
 
@@ -31,11 +29,12 @@ proc addLocalValidator*(pool: var ValidatorPool,
                         idx: int,
                         pubKey: ValidatorPubKey,
                         privKey: ValidatorPrivKey,
-                        randaoSecret: RandaoSecret) =
-  pool.validators[pubKey] = AttachedValidator(idx: idx,
+                        randaoSecret: Randao) =
+  let v = AttachedValidator(idx: idx,
                             kind: inProcess,
                             privKey: privKey,
                             randaoSecret: randaoSecret)
+  pool.validators[pubKey] = v
 
 proc getValidator*(pool: ValidatorPool,
                    validatorKey: ValidatorPubKey): AttachedValidator =
@@ -64,3 +63,11 @@ proc signAttestation*(v: AttachedValidator,
     # send RPC
     discard
 
+proc randaoReveal*(v: AttachedValidator, commitment: Eth2Digest): Future[Eth2Digest] {.async.} =
+  if v.kind == inProcess:
+    result = v.randaoSecret.reveal(commitment)
+  else:
+    # TODO:
+    # send RPC
+    discard
+